Census Day Wasn't Always April 1st

Who cares when the Census was taken? 

Turns out, knowing when Census Day falls can be helpful in narrowing down possible birth, marriage, and death dates.

One New York ancestor was enumerated with her parents in the 1900 US census, then with her husband in the 1905 NY state census, taken on June 1st. By searching between June, 1900 and May, 1905, and using creative spelling, I was able to find her marriage in early 1905.

By the time of the 1910 US census, she and her husband had one daughter...later that year, after Census Day, another daughter was born who wouldn't show up in a NY state census until 1915.

For the upcoming release of the 1950 US Census, I was particularly interested that enumerators were required to fill out a separate Infant Card for every baby born in January, February, or March of that year. If someone was born in the census year of 1950 a few days or weeks before the Census Day of April 1st, there will be an Infant Card for that person, loaded with extra details about the parents and the baby! Unfortunately, Infant Cards were not retained so we never saw those. Darn it.

Census Day Was Not Always Fixed

As shown in the graphic at top, Census Day wasn't always one fixed date. Early in the nation's history, enumerators visited households to record information as of the "first Monday in August." The idea was to avoid taking farmers out of the fields during planting or harvesting.

In 1830, Census Day was standardized as June 1st, another date that didn't conflict with agricultural responsibilities.

In 1910, the date was changed to April 15th...in 1920, the date became January 1st...and then, in 1930, the date was fixed as April 1st, where it remains.

I like to keep this list of Census Day dates handy so I can correlate with other clues as I research my family's past.